Push-push ring resonator oscillator

Abstract

A push-push microwave oscillator has two branch oscillators fabricated of a transistor and transmission line elements extending from terminals of the transistor, and a resonator which is fabricated of an annulus of superconductor material and serves to phase lock oscillations of the two branch oscillators. The superconductor material is a composite of a rare earth element and copper oxide such as yttrium-barium-copper oxide. A first transmission line in each of the branch oscillators extends past the resonator with a spacing to provide for electromagnetic coupling between the branch oscillator and the resonator. A second transmission line in each of the branch oscillators has a length equal to approximately one-quarter wavelength of the oscillation frequency to tune the branch oscillator to a common oscillation frequency. A third transmission line in each of the branch oscillators extends towards a junction point to form a summing unit for summing oscillations of the two branch oscillators to provide an output signal of the oscillator. The oscillator is constructed in stripline or microstrip form wherein components of the branch oscillators are coplanar with the resonator and are spaced apart from a ground plane by a dielectric layer of alumina or lanthanum aluminate. Power is extracted at an even multiple of the fundamental frequency, and has a improved accuracy of frequency and reduced phase noise, the latter arising because of a characteristic of the superconductor material wherein its microwave surface resistance increase proportionally with a square of an increase in frequency.

What is claimed is: 
     
       1. A push-push superconductor resonator oscillator comprising: a resonator comprising an annulus of superconductor material;   a first oscillator and a second oscillator phase locked by said resonator; and   means for summing oscillation signals produced by said first and said second oscillators to provide an output signal from said superconductor resonator oscillator.   
     
     
       2. A superconductor resonator oscillator according to claim 1 wherein each of said first and said second oscillators comprises an active element and a plurality of transmission lines connected to terminals of the active element, wherein a first transmission line of each of said first and said second oscillators provides for electromagnetic coupling to said resonator to accomplish said phase locking. 
     
     
       3. A superconductor resonator oscillator according to claim 2 wherein a second transmission line in each of said first and said second oscillators has a length which tunes the respective one of said first and said second oscillators to a specific frequency, and wherein the active element in each of said first and said second oscillators is a transistor. 
     
     
       4. A superconductor resonator oscillator according to claim 3 wherein said first and said second oscillators are constructed in a configuration coplanar with a plane of said annulus, said superconductor resonator oscillator including a ground plane parallel to the plane of said resonator and a dielectric layer disposed between said resonator and said ground plane. 
     
     
       5. A superconductor resonator oscillator according to claim 4 wherein said superconductor resonator oscillator is constructed in the form of stripline or microstrip, and the arrangement and composition of components of the superconductor resonator oscillator permit manufacture by photolithography. 
     
     
       6. A superconductor resonator oscillator according to claim 4 wherein said summing means is constructed in planar transmission line form spaced apart from said ground plane by said dielectric layer. 
     
     
       7. A superconductor resonator oscillator according to claim 6 wherein the first transmission line in said first oscillator is parallel to the first transmission line in said second oscillator, and wherein said resonator is disposed between and at equal distance from the first transmission line of said first oscillator and the first transmission line of said second oscillator. 
     
     
       8. A superconductor resonator oscillator according to claim 2 wherein the active element in each of said first and said second oscillators is operative at a common temperature with said superconductor. 
     
     
       9. A superconductor resonator oscillator according to claim 8 wherein said common temperature is less than or equal to approximately 90 degrees Kelvin, and said superconductor material is a composite of a rare earth element and copper oxide. 
     
     
       10. A superconductor resonator oscillator according to claim 9 wherein said superconductor material is yttrium-barium-copper oxide. 
     
     
       11. A superconductor resonator oscillator according to claim 10 wherein said first and said second oscillators are constructed in a coplanar configuration with a plane of said resonator, said superconductor resonator oscillator includes a ground plane parallel to the plane of said resonator and a dielectric layer disposed between said resonator and said ground plane, and said dielectric layer is alumina or lanthanum aluminate. 
     
     
       12. A push-push superconductor resonator oscillator comprising: a resonator constructed in stripline or microstrip form, said resonator comprising a disk of superconductor material, said disk having annular or solid configuration;   a first oscillator and a second oscillator phase locked by said resonator; and   means for summing oscillation signals produced by said first and said second oscillators to provide an output signal from said superconductor resonator oscillator.   
     
     
       13. A superconductor resonator oscillator according to claim 12 wherein each of said first and said second oscillators comprises an active element and a plurality of transmission lines connected to terminals of the active element, wherein a first transmission line of each of said first and said second oscillators provides for electromagnetic coupling to said resonator to accomplish said phase locking, said first transmission line of each of said first and said second oscillators being constructed in stripline or microstrip form. 
     
     
       14. A superconductor resonator oscillator according to claim 13 wherein a second transmission line in each of said first and said second oscillators has a length which tunes the oscillator to a specific frequency, and wherein the active element in each of said first and said second oscillators is a transistor, and the configuration of said resonator is a circular annulus or a square annulus or a circular solid or a rectangular solid.